package com.curtain.utils.crypt.auth;

import java.io.File;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Calendar;
import java.util.Random;

public class AuthCode {
	
	public static final String AUTH_CODE_PWD = "WHATAGOODDAY821734HELLO";

    private static final class DiscuzAuthcodeMode {
        private static final int ENCODE = 0;
        private static final int DECODE = 1;
    }

    // private static MD5 md5 = new MD5();  
    // private static BASE64 base64 = new BASE64();  
  
    // / <summary>  
    // / 从字符串的指定位置截取指定长度的子字符串  
    // / </summary>  
    // / <param name="str">原字符串</param>  
    // / <param name="startIndex">子字符串的起始位置</param>  
    // / <param name="length">子字符串的长度</param>  
    // / <returns>子字符串</returns>  
    public static String CutString(String str, int startIndex, int length) {  
        if (startIndex >= 0) {  
            if (length < 0) {  
                length = length * -1;  
                if (startIndex - length < 0) {  
                    length = startIndex;  
                    startIndex = 0;  
                } else {  
                    startIndex = startIndex - length;  
                }  
            }  
  
            if (startIndex > str.length()) {  
                return "";  
            }  
  
        } else {  
            if (length < 0) {  
                return "";  
            } else {  
                if (length + startIndex > 0) {  
                    length = length + startIndex;  
                    startIndex = 0;  
                } else {  
                    return "";  
                }  
            }  
        }  
  
        if (str.length() - startIndex < length) {  
  
            length = str.length() - startIndex;  
        }  
  
        return str.substring(startIndex, startIndex + length);  
    }  
  
    // / <summary>  
    // / 从字符串的指定位置开始截取到字符串结尾的了符串  
    // / </summary>  
    // / <param name="str">原字符串</param>  
    // / <param name="startIndex">子字符串的起始位置</param>  
    // / <returns>子字符串</returns>  
    public static String CutString(String str, int startIndex) {
        return CutString(str, startIndex, str.length());  
    }  
  
    // / <summary>  
    // / 返回文件是否存在  
    // / </summary>  
    // / <param name="filename">文件名</param>  
    // / <returns>是否存在</returns>  
    public static boolean FileExists(String filename) {  
        File f = new File(filename);
        return f.exists();  
    }  
  
    // / <summary>  
    // / MD5函数  
    // / </summary>  
    // / <param name="str">原始字符串</param>  
    // / <returns>MD5结果</returns>  
    public static String MD5(String str) {  
        // return md5.convert(str);  
        StringBuffer sb = new StringBuffer();  
        String part = null;  
        try {  
            MessageDigest md = MessageDigest.getInstance("MD5");  
            byte[] md5 = md.digest(str.getBytes());  
  
            for (int i = 0; i < md5.length; i++) {  
                part = Integer.toHexString(md5[i] & 0xFF);  
                if (part.length() == 1) {  
                    part = "0" + part;  
                }  
                sb.append(part);  
            }  
  
        } catch (NoSuchAlgorithmException ex) {  
        }  
        return sb.toString();  
    }  
  
    // / <summary>  
    // / 字段串是否为Null或为""(空)  
    // / </summary>  
    // / <param name="str"></param>  
    // / <returns></returns>  
    public static boolean StrIsNullOrEmpty(String str) {  
        // #if NET1  
        if (str == null || str.trim().equals("")) {  
            return true;  
        }  
  
        return false;  
    }  
  
    // / <summary>  
    // / 用于 RC4 处理密码  
    // / </summary>  
    // / <param name="pass">密码字串</param>  
    // / <param name="kLen">密钥长度，一般为 256</param>  
    // / <returns></returns>  
    static private byte[] GetKey(byte[] pass, int kLen) {  
        byte[] mBox = new byte[kLen];  
  
        for (int i = 0; i < kLen; i++) {  
            mBox[i] = (byte) i;  
        }  
  
        int j = 0;  
        for (int i = 0; i < kLen; i++) {  
  
            j = (j + (int) ((mBox[i] + 256) % 256) + pass[i % pass.length])  
                    % kLen;  
  
            byte temp = mBox[i];  
            mBox[i] = mBox[j];  
            mBox[j] = temp;  
        }  
  
        return mBox;  
    }  
  
    // / <summary>  
    // / 生成随机字符  
    // / </summary>  
    // / <param name="lens">随机字符长度</param>  
    // / <returns>随机字符</returns>  
    public static String RandomString(int lens) {  
        char[] CharArray = { 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'j', 'k',  
                'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w',  
                'x', 'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9' };  
        int clens = CharArray.length;  
        String sCode = "";  
        Random random = new Random();  
        for (int i = 0; i < lens; i++) {  
            sCode += CharArray[Math.abs(random.nextInt(clens))];  
        }  
        return sCode;  
    }  
  
    // / <summary>  
    // / 使用 Discuz authcode 方法对字符串加密  
    // / </summary>  
    // / <param name="source">原始字符串</param>  
    // / <param name="key">密钥</param>  
    // / <param name="expiry">加密字串有效时间，单位是秒</param>  
    // / <returns>加密结果</returns>  
    public static String authcodeEncode(String source, String key, int expiry) {  
        return authcode(source, key, DiscuzAuthcodeMode.ENCODE, expiry);
  
    }  
  
    // / <summary>  
    // / 使用 Discuz authcode 方法对字符串加密  
    // / </summary>  
    // / <param name="source">原始字符串</param>  
    // / <param name="key">密钥</param>  
    // / <returns>加密结果</returns>  
    public static String authcodeEncode(String source, String key) {  
        return authcode(source, key, DiscuzAuthcodeMode.ENCODE, 0);
  
    }  
  
    // / <summary>  
    // / 使用 Discuz authcode 方法对字符串解密  
    // / </summary>  
    // / <param name="source">原始字符串</param>  
    // / <param name="key">密钥</param>  
    // / <returns>解密结果</returns>  
    public static String authcodeDecode(String source, String key) {  
        return authcode(source, key, DiscuzAuthcodeMode.DECODE, 0);
  
    }  
  
    // / <summary>  
    // / 使用 变形的 rc4 编码方法对字符串进行加密或者解密  
    // / </summary>  
    // / <param name="source">原始字符串</param>  
    // / <param name="key">密钥</param>  
    // / <param name="operation">操作 加密还是解密</param>  
    // / <param name="expiry">加密字串过期时间</param>  
    // / <returns>加密或者解密后的字符串</returns>  
    private static String authcode(String source, String key,  
            int operation, int expiry) {
        try {  
            if (source == null || key == null) {  
                return "";  
            }  
  
            int ckey_length = 4;  
            String keya, keyb, keyc, cryptkey, result;  
  
            key = MD5(key);  
  
            keya = MD5(CutString(key, 0, 16));  
  
            keyb = MD5(CutString(key, 16, 16));  
  
            keyc = ckey_length > 0 ? (operation == DiscuzAuthcodeMode.DECODE ? CutString(
                    source, 0, ckey_length) : RandomString(ckey_length))  
                    : "";  
  
            cryptkey = keya + MD5(keya + keyc);  
  
            if (operation == DiscuzAuthcodeMode.DECODE) {
                byte[] temp;  
  
                temp = Base64.decode(CutString(source, ckey_length));
                result = new String(RC4(temp, cryptkey));  
                if (CutString(result, 10, 16).equals(  
                        CutString(MD5(CutString(result, 26) + keyb), 0, 16))) {  
                    return CutString(result, 26);  
                } else {  
                    temp = Base64.decode(CutString(source + "=", ckey_length));  
                    result = new String(RC4(temp, cryptkey));  
                    if (CutString(result, 10, 16)  
                            .equals(CutString(  
                                    MD5(CutString(result, 26) + keyb), 0, 16))) {  
                        return CutString(result, 26);  
                    } else {  
                        temp = Base64.decode(CutString(source + "==",  
                                ckey_length));  
                        result = new String(RC4(temp, cryptkey));  
                        if (CutString(result, 10, 16).equals(  
                                CutString(MD5(CutString(result, 26) + keyb), 0,  
                                        16))) {  
                            return CutString(result, 26);  
                        } else {  
                            return "2";  
                        }  
                    }  
                }  
            } else {  
                source = "0000000000" + CutString(MD5(source + keyb), 0, 16)  
                        + source;  
  
                byte[] temp = RC4(source.getBytes("UTF-8"), cryptkey);  
  
                return keyc + Base64.encodeBytes(temp);  
  
            }  
        } catch (Exception e) {  
            return "";  
        }  
  
    }  
  
    // / <summary>  
    // / RC4 原始算法  
    // / </summary>  
    // / <param name="input">原始字串数组</param>  
    // / <param name="pass">密钥</param>  
    // / <returns>处理后的字串数组</returns>  
    private static byte[] RC4(byte[] input, String pass) {  
        if (input == null || pass == null)  
            return null;  
  
        byte[] output = new byte[input.length];  
        byte[] mBox = GetKey(pass.getBytes(), 256);  
  
        // 加密  
        int i = 0;  
        int j = 0;  
  
        for (int offset = 0; offset < input.length; offset++) {  
            i = (i + 1) % mBox.length;  
            j = (j + (int) ((mBox[i] + 256) % 256)) % mBox.length;  
  
            byte temp = mBox[i];  
            mBox[i] = mBox[j];  
            mBox[j] = temp;  
            byte a = input[offset];  
  
            // byte b = mBox[(mBox[i] + mBox[j] % mBox.Length) % mBox.Length];  
            // mBox[j] 一定比 mBox.Length 小，不需要在取模  
            byte b = mBox[(toInt(mBox[i]) + toInt(mBox[j])) % mBox.length];  
  
            output[offset] = (byte) ((int) a ^ (int) toInt(b));  
        }  
  
        return output;  
    }  
  
    public static int toInt(byte b) {  
        return (int) ((b + 256) % 256);  
    }  
  
    public long getUnixTimestamp() {  
        Calendar cal = Calendar.getInstance();  
        return cal.getTimeInMillis() / 1000;  
    }  
/*

    public static void main(String[] args) {  
        
        String test = "phone=13800000000";  
        String key = "ABCDEFGKINGSGAMEGOLDKEYST1501290";  
        String afStr = AuthCode.authcodeEncode(test, key);  
        System.out.println("--------encode:" + afStr);  
        long lStart = System.currentTimeMillis();  
        System.out.println("解码后：" + AuthCode.authcodeDecode(afStr, key));  
        long lUseTime = System.currentTimeMillis() - lStart;  
        System.out.println("加解密耗时：" + lUseTime + "毫秒");  
        String deStr = AuthCode  
                .authcodeDecode(  
                        "5709xe3dV2v/mQxBHut//Fzn1tj53ZT/87kQ3VB5W/bGuQRAqd9+Exq7",  
                        "xxoo");  
        System.out.println("--------decode:" + deStr);  
  
    }  
*/

}
